1. Field of the Invention
The present invention relates to an analog electronic timepiece including plural indicator wheels. The present invention particularly relates to an analog electronic timepiece including a plurality of indicator wheels coaxially rotated and attaching indicating members such as indicators to the respective indicator wheels.
The invention can realize an analog electronic timepiece having a high degree of freedom in designing an indicator and having a novel and easy-to-see indicating portion.
2. Background Information
Generally, a xe2x80x9cmovement (machine body)xe2x80x9d of an analog electronic timepiece is provided with a main plate constituting a board of the movement. Further, a movement (machine body) contained in a wrist watch case is referred to as xe2x80x9ccompletexe2x80x9d. A wrist watch case includes a case body, a xe2x80x9ccase backxe2x80x9d and xe2x80x9cglassxe2x80x9d.
Further, in both sides of a main plate, a side having a dial is referred to as xe2x80x9cback sidesxe2x80x9d of an analog electronic timepiece and in the both sides of the main plate, a side opposed to the dial is referred to as xe2x80x9ctop sidexe2x80x9d of an analog electronic timepiece. Further, a train wheel integrated to the top side of an analog electronic timepiece is referred to as xe2x80x9ctop train wheelxe2x80x9d and a train wheel integrated to the back side of an analog electronic time piece is referred to as xe2x80x9cback train wheelxe2x80x9d.
Therefore, a xe2x80x9ccase backxe2x80x9d of a wrist watch case is arranged to face the xe2x80x9ctop sidexe2x80x9d of an analog electronic timepiece and xe2x80x9cglassxe2x80x9d of a wrist watch case is arranged to face the xe2x80x9cback sidexe2x80x9d of the analog electronic timepiece and is arranged to face a dial.
Further, numerals from xe2x80x9c1xe2x80x9d to xe2x80x9c12xe2x80x9d or the like are frequently described on a dial or an outer peripheral portion of a case (case body, bezel or the like) of an analog electronic timepiece. Therefore, respective directions along the outer peripheral portion of the analog electronic timepiece are expressed by using the numerals. For example, in the case of a wrist watch, an upper direction and an upper side of the wrist watch are respectively referred to as xe2x80x9c12 o""clock directionxe2x80x9d and xe2x80x9c12 o""clock sidexe2x80x9d, a right direction and a right side of the wrist watch are respectively referred to as xe2x80x9c3 o""clock directionxe2x80x9d and xe2x80x9c3 o""clock sidexe2x80x9d, a lower direction and a lower side of the wrist watch are respectively referred to as xe2x80x9c6 o""clock directionxe2x80x9d and xe2x80x9c6 o""clock sidexe2x80x9d and a left direction and a left side of the wrist watch are respectively referred to as xe2x80x9c9 o""clock directionxe2x80x9d and xe2x80x9c9 o""clock sidexe2x80x9d.
Generally, according to an analog electronic timepiece, a drive portion, a control portion and a top train wheel are integrated to a top side of the timepiece. Further, in the wrist watch, a switch portion may be integrated to the top side of the timepiece, may be integrated to the back side of the timepiece, or may be integrated to both of the top side and the back side of the timepiece.
A conventional three hands analog electronic timepiece is constituted such that by rotation of a rotor constituting a step motor, a second wheel and pinion (corresponding to a wheel for indicating second) is decelerated to rotate via rotation of a fifth wheel and train, by rotation of the second wheel and pinion, a center wheel and pinion (corresponding to a wheel for indicating minute) is decelerated to rotate via rotation of a third wheel and pinion and by rotation of the center wheel and pinion, an hour wheel (corresponding to a wheel for indicating hour) is decelerated to rotate via rotation of a minute wheel.
A rotational center of the second wheel and pinion, a rotational center of the center wheel and pinion and a rotational center of the hour wheel are arranged at the same position. That is, the second wheel and pinion, the center wheel and pinion and the hour wheel are constituted to rotate coaxially.
A cylindrical portion of the center wheel and pinion is arranged to penetrate a cylindrical portion of the hour wheel and a shaft portion of the second wheel and pinion is arranged to penetrate the cylindrical portion of the center wheel and pinion. A second hand is attached to the second wheel and pinion, a minute hand is attached to the center wheel and pinion and an hour hand is attached to the hour wheel. Further, in the case of a two hands analog electronic timepiece, a secondhand is not provided.
A structure of such a conventional analog electronic timepiece is disclosed in, for example, Japanese Patent Laid-Open No. 86283/1978, Japanese Patent Laid-Open NO. 67678/1980, Japanese Patent Laid-Open No. 189577/1983 or the like.
Further, in Japanese Utility Model. Laid-Open No. 96489/1988, there is disclosed a structure of a timepiece having a cover member in a projected shape and arranged with an hour hand, a minute hand and a second hand bent to follow a shape of an inner side of the cover member in an order of proximity to a movement.
However, according to the conventional analog electronic timepiece, the cylindrical portion of the center wheel and pinion is arranged to penetrate the cylindrical portion of the hour wheel, the shaft portion of the second wheel and pinion is arranged to penetrate the cylindrical portion of the center wheel and pinion and therefore, a degree of freedom of designing a second hand, a minute hand and an hour hand is considerably restricted.
In other words, according to the conventional analog electronic timepiece, when the second wheel and pinion is attached with an indicator having large moment of inertia such as a thick indicator, a long indicator, or an indicator having a special shape, a value of the moment of inertia of the indicator is restricted and there poses a problem that an indicator having large moment of inertia cannot be attached to the second wheel and pinion.
Further, according to the conventional analog electronic timepiece, when an hour hand having a large moment of inertia (that is, having a large weight, three-dimensional shape or the like) is attached to a cylindrical portion of an hour wheel having a large rotation drive torque, an hour hand base seat constituting a base of the hour hand is attached to a cylindrical portion of the hour wheel and the hour hand having a large moment of inertia is attached to the hour hand base seat. By this construction, the operability for attaching and detaching the hour hand is difficult to accomplish.
It is an object of the invention to provide an analog electronic timepiece capable of attaching an hour hand not to a cylindrical portion but to a shaft portion.
It is another object of the invention to enhance a degree of freedom of designing a second hand, a minute hand and an hour hand in an analog electronic timepiece.
In order to resolve the above-described problem in the conventional art, according to an aspect of the invention, there is provided an analog electronic timepiece comprising a rotor constituting a motor, a first indicator wheel decelerated to rotate based on rotation of the rotor, a second indicator wheel decelerated to rotate based on rotation of the first indicator wheel, and a third indicator wheel decelerated to rotate based on rotation of the second indicator wheel.
According to the aspect of the electronic timepiece of the invention, the first indicator wheel includes a cylindrical portion, the second indicator wheel includes a cylindrical portion and the third indicator wheel includes a shaft portion, the first indicator wheel, the second indicator wheel and the third indicator wheel being constituted to coaxially rotate by making respective rotational centers thereof the same as each other.
Further, according to the aspect of the electronic timepiece of the invention, the cylindrical portion of the second indicator wheel is constituted to penetrate the cylindrical portion of the first indicator wheel and the shaft portion of the third indicator wheel is constituted to penetrate the cylindrical portion of the second indicator wheel.
In one example, the first indicator wheel is a second wheel and pinion, the second indicator wheel is a center wheel and pinion and the third indicator wheel is an hour wheel.
In another example, the first indicator wheel is the second wheel and pinion, the second indicator wheel is a center wheel and pinion and the third indicator wheel is a 24 hour wheel.
Further, the electronic timepiece of the invention further comprises a first indicating member attached to the cylindrical portion of the first indicator wheel, a second indicating member attached to the cylindrical portion of the second indicator wheel, and a third indicating member attached to the shaft portion of the third indicator wheel.
For example, the first indicating member is a second hand, the second indicating member is a minute hand and the third indicating member is an hour hand.
Alternatively, the first indicating member is the second hand, the second indicating member is the minute hand and the third indicating member is a 24 hour hand.
Alternatively, the first indicating member is the minute hand, the second indicating member is the hour hand the third indicating member is the 24 hour hand.
The electronic timepiece of the invention is preferably constituted so that the first indicator wheel is rotated by one rotation per minute, the second indicator wheel is rotated by one rotation per hour and the third indicator wheel is rotated by one rotation per 12 hours.
Further, the electronic timepiece of the invention may be constituted so that the first indicator wheel is rotated by one rotation per minute, the second indicator wheel is rotated by one rotation per hour and the third indicator wheel is rotated by one rotation per 24 hours.
Further, the electronic timepiece of the invention may be constituted so that the first indicator wheel is rotated by one rotation per hour, the second indicator wheel is rotated by one rotation per 12 hours and the third indicator wheel is rotated by one rotation per 24 hours.
Further, the electronic timepiece of the invention is preferably provided with a center pipe for the first indicator wheel for rotatably guiding at least a portion of an inner peripheral face of the cylindrical portion of the first indicator wheel.
Further, the electronic timepiece of the invention is preferably provided with a center pipe for the second indicator wheel for rotatably guiding at least a portion of an inner peripheral face of the cylindrical portion of the second indicator wheel.
Further, the electronic timepiece of the invention can also be constituted to include a center pipe for the second indicator wheel for rotatably guiding at least a portion of an inner peripheral face of the cylindrical portion of the second indicator wheel, wherein at least a portion of an inner peripheral face of the cylindrical portion of the first indicator wheel is rotatably guided by an outer peripheral face of the cylindrical portion of the second indicator wheel.
By the foregoing construction, there can be realized an analog electronic timepiece having a high degree of freedom of designing indicators and a novel and easy-to-see indicating portion. Further, operation of indicators attached to indicator wheels can be stabilized.